Possibly, but you have to be suspect of any converter that requires a heat sink. The whole idea of using a converter is to conserve power improving run times and generating less heat that can make a mod uncomfortable in the hand. A really good converter with high efficiency has no need of heat sinks since it shouldn't get that hot in the first place. Heat sinks allow crappy converters to put out the power good ones can without them.

Very true, all this stuff is moot if you use a wholly mechanical mod, but then there's the dreaded battery fade. It's less of a problem than it used to be, but it's still there. Of course things like battery fuel gauges and power meters are kind of a critical feature, they're not necessities, but they help a lot.

Very true, all this stuff is moot if you use a wholly mechanical mod, but then there's the dreaded battery fade. It's less of a problem than it used to be, but it's still there. Of course things like battery fuel gauges and power meters are kind of a critical feature, they're not necessities, but they help a lot.

if truth be told..........there is plenty of battery fade on regulated mods too and when I build the coils right, battery fade is what I enjoy

Something is wrong with your mod builds. Only when at specified on data sheet range tolerances ie: close to needing charge..

They are guaranteed/warrantied to not do that.

If your batt's are fading quickly, then you really want to keep a better eye on how far you let them drain before recharging... I'll bet you're over-discharging them, and killing them early.

Note* this INCLUDES temporary over-drainage from pulling too much current at or near the low capacity level of the battery. Common with regulated mods, and depending on your atty setup, mechanicals as well.

Thanks. That was the plan but I somehow managed to wire it up so the usb out only works when the button is pressed. Wasn't really a feature I wanted, just happened to be the charge board I had on hand.

if truth be told..........there is plenty of battery fade on regulated mods too

Well it depends. The mods I build have zero battery fade by design. The mod will flag a low battery when battery voltage is too low to provide the desired output. However with mods that don't have that ability, like ones that are simply regulated, you can get battery fade if battery voltage falls below what the regulator requires to provide a selected output.

Maybe coil break in fsor is having IDK thats strange. It does happen on mods like an ego twist but thats only because it has those tiny 30ga wires put better wires on it and it goes all the way to cutoff..

Wow I remember reading up on how the ego twist was revolutionary for power and size.

This is a window that shows the set up for the unregulated mods. I don't know what the watts are on the MOSFET but I do see that there is a 15k resistor being used.

You posted it was the best diagram ever. I think xomby was saying no to the death of no.well I am saying it, that link is dead to me Have you seen the mech and fet recommended diagrams in this post? Come on man/maa'm thats like a kindergarten mech compared to this post of mechs.. Also in this post you will know what fet/fets you are using and why it makes your mech one of the most badarse/safest mechs ever.Not ragging on awesome everything in one place link but whoa awesome is in this thread.

You posted it was the best diagram ever. I think xomby was saying no to the death of no.well I am saying it, that link is dead to me Have you seen the mech and fet recommended diagrams in this post? Come on man/maa'm thats like a kindergarten mech compared to this post of mechs.. Also in this post you will know what fet/fets you are using and why it makes your mech one of the most badarse/safest mechs ever.Not ragging on awesome everything in one place link but whoa awesome is in this thread.

Basic mechs so july of 2014

My opinion and being silly bout my opinion..

Visus, there's a thousand and one ways to wire up a mod. Some are arguably 'better' than others, but try to reign in the put-downs. Everyone has different levels of skill/learning and tools/ability to create a mod, and we ALL started knowing diddly squat at some point. Maybe he/she's after something specific, or maybe they just want to know if a design like this would work at all.

As an aside, once you start throwing switches and mosfets into the mix, it's no longer a "mech" mod. Strictly speaking, using wires or anything other than a screw and spring as a "switch" precludes a mod from being a "mech mod". We're talking about box-mods here. PV, still, if you like. But not "mech".

The second link did work... google image result.

This looks like an unregulated 3.7v mod with a... N-chan? Besides the fact that they don't list the part# for the mosfet, so you don't really know what you're getting. Unless the n-chan's properties make it to cutoff at around 3.1v, there's no low-voltage reference, so you could kill your batteries if you run them down too low.

The wiring diagram looks proper, although Craig or BT could take a quick look and verify.

Other than the mystery mosfet, it's a decent design for a simple unregulated mod. The fact that it includes fuses is a plus. The fact that the diagram is easy to read is a plus. But lack of details on the mosfet is a big red FAIL.

I included the diagram here because it's clean and pretty. @Reckful -- This would work with any sized battery, not just 18650.

Visus, there's a thousand and one ways to wire up a mod. Some are arguably 'better' than others, but try to reign in the put-downs. Everyone has different levels of skill/learning and tools/ability to create a mod, and we ALL started knowing diddly squat at some point. Maybe he/she's after something specific, or maybe they just want to know if a design like this would work at all.

As an aside, once you start throwing switches and mosfets into the mix, it's no longer a "mech" mod. Strictly speaking, using wires or anything other than a screw and spring as a "switch" precludes a mod from being a "mech mod". We're talking about box-mods here. PV, still, if you like. But not "mech".

The second link did work... google image result.

This looks like an unregulated 3.7v mod with a... N-chan? Besides the fact that they don't list the part# for the mosfet, so you don't really know what you're getting. Unless the n-chan's properties make it to cutoff at around 3.1v, there's no low-voltage reference, so you could kill your batteries if you run them down too low.

The wiring diagram looks proper, although Craig or BT could take a quick look and verify.

Other than the mystery mosfet, it's a decent design for a simple unregulated mod. The fact that it includes fuses is a plus. The fact that the diagram is easy to read is a plus. But lack of details on the mosfet is a big red FAIL.

I included the diagram here because it's clean and pretty. @Reckful -- This would work with any sized battery, not just 18650.

Lol Xomby ya read this post that same diagram is in this post. I was not putting it down jackits not a basic mech its very and awesome but as I said it's right here with whats what added.

The reason I posted it once more Virus was because some one added that it was a dead link, that was all but back on topic. Thanks for clearing that up a little bit more for me since I seemed to not have added the additional information XombyCraft.

The reason I posted it once more My master ViSus was because some one added that it was a dead link, that was all but back on topic. Thanks

Fixt it for ya

was just being silly about it that mech with parts is in this post but the guy who runs that site also has a video on youtube showing you how to wire it, dont know if you know that, he makes some good vids on how to wire a dna and okr..

Not going to work well other than with series cells. The gate-source threshold is too high for a single cell or parallel cells. That one doesn't show an "on-state resistance versus gate-source voltage" chart, seems most of those older style MOSFETs do not. Looking at the transfer characteristics that are provided, it will barely turn on and probably burn up if battery voltage gets down to 3V. Even at 3.7V on-state resistance will be too high.

Ok Craig, I need some expert help. Duel 18650 in parallel capable of sub ohming. I have 10-SI7175DP mosfets and 10-NCP300HSN30T1G low voltage cutoffs. I have all the switches. (more than one box). Im having issues finding fuses that aren't the size of a truck. If Im thinking of this right that's 4 fuses around 7- 10amps each with a hold current around 4 - 7amps or so. That would be 16-28amps hold and around 40amp trip correct? That's if you ever maxed it out. I think I have thought about this so much I have confused myself

Yeah it's easy to get confused by too many specs, happens to me too sometimes.

The problem with high currents is you can get to a point where any combination of PTC fuses just won't be able to do the job. If you're running parallel 18650s and looking for a maximum over 40A, you need to run close to the trip current otherwise it will take so much current to trip the fuses, they aren't going to do much good in terms of protection.

That being the case, you probably should run two 4 or 5A hold fuses on each cell and just take what you get in terms of maximal current demand. You're probably not going to be able to guarantee a 40A load. At a nominal 3.7V, you're looking at an atomizer resistance of less than 100 mohms. 200 mOhms is probably practical in terms of the lowest you would go and a quad set of 4A hold fuses can support that no problem. A set like that will also provide a low enough trip current the fuses will actually protect the batteries and circuit if a short or reverse polarity condition occurs.

This one is going to be the smallest best PTC fuse, four of them will get you up to 36A;

Honestly its very doubtful it will ever see anywhere close to that. Those fuses will work out well with the smd mosfets. Seems like Im going to be doing some dremel work. If I can get it right everything should fit on one small board. Thanks Craig

Just another way to it. If you don't short or batts old and do not make a 30A+ runway to the other you wont need it anyway lol..They do sell resettable blade fuses @ 40A-50A and they would be about the same size as a smd build, tad bigger http://www.optifuse.com/cirbreakType1.php#

I have a crap load of those type and circuit breakers to. ( I owned a custom car stereo shop). I had actually thought of trying one just to see how well it would work. In theory it should work as well as any other type fuse.

Those fuses can do the job for high currents if you don't mind replacing them. It's actually pretty rare that you run into an issue so it may be practical. I haven't seen an over-current issue in quite some time myself. All of my mods use non-removable cells so I don't know how often you would run into the reverse polarity situation.

There are some issues in using those blade fuses. They do have a little more resistance than a good set of PTC fuses. Also, they are slow blow and intended for automotive applications where the power supply has a much higher maximal current and voltage. They mainly protect wiring and not electronics. There's a big difference in maximal current output comparing a car battery to a small Li-Ion battery.

For example, a 30A blade fuse takes about 10 seconds to blow with a 50A fault current. That may not provide the protection required for some electronics. You'd have to check the charts with any blade fuse to make sure the fuse will actually protect the circuit. Here's an example;

There's lots of other single use fuse types you can use. For example ceramic fast-blo fuses are often used in multi-meters to protect the ammeters in them. That might be a better option in terms of protection.

I have been playing around with this for some time trying to find out which one would be good for a mosfet switch. I was thinking that a n-channel mosfet, located here (40V 195A 375W) should be good enough.

Quick question. Can I solder to the body on this N channel? I'm having trouble fitting 16 gauge wires to two pins so close together. I think I saw somewhere that the body connects to drain but I can't find it now.

Allrighty, Im stuck. So i built the okr..and the raptor 120 and i wanted to build a mosfet mech box. so i gets me to looking around and reading and it seems everybody was using the irlb3034 n-fet for it. so went looking for diagram..found said diegram and compared it to others...yep..its for an n-fet build...not a p-fet. I say to myself..this looking ALOT eaisier than stuffing a raptor in a 1590g box..(yeash!) so i go order...and since i proatice good ordering ..i ordered ten of em..it was cheaper by over a buck..wait a week..and bamp! there here . I go to build it all..lay it out with everything...solder it up little heatshrink..and looks good and clean.

I went back and checked it all..tested the volts...it was 3.3 under load...and the mosfet got REALLY hot...the hotter it got the more it vaped...so i unhooked it to try to figure it out..iv changed out for another (couple) fets and thay all do the same thing..mosfet got really hot.. with barly any vape.

so, in short..im stuck. btw..did read all over these forums for answers befor i posted and couldnt find any answers..

Allrighty, Im stuck. So i built the okr..and the raptor 120 and i wanted to build a mosfet mech box. so i gets me to looking around and reading and it seems everybody was using the irlb3034 n-fet for it. so went looking for diagram..found said diegram and compared it to others...yep..its for an n-fet build...not a p-fet. I say to myself..this looking ALOT eaisier than stuffing a raptor in a 1590g box..(yeash!) so i go order...and since i proatice good ordering ..i ordered ten of em..it was cheaper by over a buck..wait a week..and bamp! there here . I go to build it all..lay it out with everything...solder it up little heatshrink..and looks good and clean.

I went back and checked it all..tested the volts...it was 3.3 under load...and the mosfet got REALLY hot...the hotter it got the more it vaped...so i unhooked it to try to figure it out..iv changed out for another (couple) fets and thay all do the same thing..mosfet got really hot.. with barly any vape.

so, in short..im stuck. btw..did read all over these forums for answers befor i posted and couldnt find any answers..

so any thoughts?

Sorry but the link to your diagram requires membership to that forum so I can't see your diagram.

You mentioned that you soldered it up to the little heatsink. Is that the base heatsink on the mosfet? I believe that the base is the same as the "D" Drain pin.

grrrr, i still dont know what i did wrong, but i took everything apart and started from scratch. I used davids diagram from the post up above and made sure it was all good solder connections. I must of had a bad one because it vaped like it was suposed to. i get a .4v drop under load with a .10 coil. the only heat issues are from the atty lol. to avoid blowing up the my battiries im using one of the new 26650 batteries that "say" it has a 75amp pulse limit. so far so good. now i just have to try my cutting skills out for the voltmeter. As allways, ty all for paving the way, couldnt of done any of it without this forum.